Hybrid thermal management of electronic device

ABSTRACT

An enclosure with hybrid thermal management for a heat-generating electronic device comprises a passive heat sink for conducting heat away from the electronic device, a cold skin adapted to slide over the top of the passive heat sink and having a front wall forming a plurality of air intake ports, and a plurality of blowers mounted inside the cold skin for drawing air into the cold skin though the air intake ports and then directing the air through the passive heat sink. In one implementation, the passive heat exchanger includes multiple thermally conductive fins adjacent to the electronic device and extending rearwardly from the intake ports, the fins being spaced apart from each other for conducting heat away from the electronic device. The blowers preferably direct air rearwardly from the intake ports in the front wall into the spaces between the thermally conductive fins.

FIELD OF THE INVENTION

The present disclosure relates to hybrid thermal management ofelectronic devices, specifically the cooling of transceivers, such as asmall form-factor pluggable (SFP) transceiver.

BRIEF SUMMARY

In accordance with one embodiment, an enclosure with hybrid thermalmanagement for a heat-generating electronic device comprises a passiveheat sink for conducting heat away from the electronic device, a coldskin adapted to slide over the top of the passive heat sink and having afront wall forming a plurality of air intake ports, and a plurality ofblowers mounted inside the cold skin for drawing air into the cold skinthough the air intake ports and then directing the air through thepassive heat sink. In one implementation, the passive heat exchangerincludes multiple thermally conductive fins adjacent to the electronicdevice and extending rearwardly from the intake ports, the fins beingspaced apart from each other for conducting heat away from theelectronic device. The blowers preferably direct air rearwardly from theintake ports in the front wall into the spaces between the thermallyconductive fins, with air being exhausted from the enclosure throughexhaust ports formed in the rear wall of the passive heat sink.

The thermally conductive fins preferably extend vertically along the airintake ports and above the intake ports, with the portions of the finsabove the air intake ports being spaced rearwardly away from the intakeports to form a space for receiving the blowers inside the cold skin.The passive heat sink preferably includes side walls forming a spacebelow the fins for receiving the heat-generating electronic device, anda front wall closing the spaces below the fins and adapted to transmitsignals to the electronic device in the space, such as optical ports totransmit optical signals to the electronic device. The electronic devicemay comprise a transceiver, such as an SFP. A controller may be coupledto the blowers for adjusting the speed of the blowers based on thetemperature in the enclosure.

The foregoing and additional aspects and embodiments of the presentdisclosure will be apparent to those of ordinary skill in the art inview of the detailed description of various embodiments and/or aspects,which is made with reference to the drawings, a brief description ofwhich is provided next.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the disclosure will becomeapparent upon reading the following detailed description and uponreference to the drawings.

FIG. 1 is the front perspective of a prior art example of an enclosure;

FIG. 2 is a front perspective example of a cold skin

FIG. 3 is a front perspective example of a single base unit enclosurewith a custom step in the fins to affix a custom cold skin;

FIG. 4 is a partial unit perspective, with the cold skin affixed to theenclosure of FIG. 3.

FIG. 5 is a full closed unit perspective of the cold skin affixed to theenclosure.

While the present disclosure is susceptible to various modifications andalternative forms, specific embodiments or implementations have beenshown by way of example in the drawings and will be described in detailherein. It should be understood, however, that the disclosure is notintended to be limited to the particular forms disclosed. Rather, thedisclosure is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of an invention as defined by theappended claims.

DETAILED DESCRIPTION

During operations, electronic devices generate heat which may cause thedevice to overheat and damage itself. Heat sinks, located near theelectronic components or surrounding the electronic components as anenclosure, transfer the thermal energy from a high temperature device toa lower temperature medium, such as air or water, either actively orpassively. The passive heat sink dissipates the hot air to a surroundingmedium through convection and/or conduction. The active heat sinks usepowered blowers or fans, to dissipate the heat and cool the device.

Existing heat sinks use passive or active thermal management, but notboth. Some dissipation methods contain the air within the enclosure,which potentially causes dust contamination. Filters within theenclosure help prevent contamination, when air remains in the enclosure.Existing heat sinks also renew oxygen within the enclosure, which causespotential fire hazards.

There is a need for an enclosure for electronic devices, which providesa hybrid thermal solution, consistently using both passive and activethermal management, the workload of each solution being dependent on thedevice's temperature. The solution needs to include dust control by useof moving air to outside of the enclosure and device. When air movesoutside the enclosure, the lack of oxygen renewal minimizes the threatof a fire, as necessary for Network Equipment Building System (NEBS)fire certification. The hybrid use of passive and active thermalmanagement provides optimized cooling in a low cost and high reliabilitymanner.

FIG. 1 shows an example prior art enclosure 100. The enclosure generallycomprises a plurality of electrical components (not shown). Thisembodiment is described in terms of an enclosure 100, comprising aplurality of transceivers (not shown) which have one or more opticalports 101 for connecting to other networking devices. The enclosurefurther comprises a plurality of fins 102 for passive heat exchange byway of convection. Generally, these devices are rack mounted, andtherefore it is desirable to access the interface from the front 120 foractions such as maintenance and configuration.

The fins 102 form a passive heat sink, to dissipate heat from internalelectrical components, such as transceivers, while the ambient air flowsthrough the fins.

Active heat sinks generally connect to one or more electronic devices.In this embodiment, the active heat sink is placed above passive heatsinks which, in this example, are the fins of the enclosure 100. Theactive heat sink, comprising fans or blowers, slide on top of passiveheat sink enclosures of the electronic devices. They are referred to ascold skins. A cold skin is a secondary active heat sink enclosure whichaffixes to a passive heat sink enclosure, and connects to one or more ofthe electronic devices within the passive heat sink enclosure. Theplurality of fans or blowers in the cold skin assist the passive heatsink in the cooling of the electronic components. The simultaneous useof a cold skin and a passive heat sink as per this embodiment, isreferred to as a hybrid thermal solution.

FIG. 2 is a front view of an embodiment of a cold skin 200, with frontaccess 220, wherein once affixed to the enclosure 100, with fin-basedpassive heat exchange, air can flow through a plurality of air intakes201 at the front of the cold skin 200, such that low profile blowers(not shown) 202 can dissipate the heat out the back of the enclosure100.

FIG. 3 shows a different enclosure 300, comprising a custom design ofthe fins 302. A section is cut from the plurality of fins 302, forming a‘step’ 303 which allows a custom cold skin 200 with a flat surface toaffix to the top of the enclosure 300, wherein the blowers 202 facedownwards on top of the removed section of fins 302, allowing for easierplacement in a rack-mounted environment. This embodiment can also beapplied to any rack-mounted size enclosure, such as 1 U, 2 U, and 4 U.

FIG. 4 shows the cold skin 200 after it affixes to the top of theenclosure 300, which may vary in form, where the custom step 303 allowsthe cold skin 200 to slide on top of the enclosure 300, to maintain aflat surface, and the blowers (not shown) 202 sit face-down directly onthe top of the fins 302.

FIG. 5 shows a closed view of the cold skin 200 affixed to the enclosure300, wherein ambient air passes through the plurality of air intakes201, where the fins 302 use convection to raise the heat to the top ofthe enclosure 300, while remaining air flows through the fins 302 andout the back of the enclosure 300 as the blowers 202 of the cold skin200 actively cool the heat and push the resulting air outside theenclosure 300 through the back. The blowers 202, attached to the coldskin 200, lie face-down at the front of the enclosure 300. The ambientair exiting the back of the blowers 202 also cools the back portion ofthe enclosure 300 before leaving the enclosure 300 through the back.

Generally, the blowers 202 are always on for hybrid thermal management,as the cold skin 200 prevents passive-only heat dissipation. Optionally,the cold skin 200 may connect to the enclosure 300, where thermalsensors in the enclosure 300 may trigger the blowers 202 to change speedbased on the operating temperature of the device.

While particular implementations and applications of the presentdisclosure have been illustrated and described, it is to be understoodthat the present disclosure is not limited to the precise constructionand compositions disclosed herein and that various modifications,changes, and variations can be apparent from the foregoing descriptionswithout departing from the spirit and scope of an invention as definedin the appended claims.

What is claimed is:
 1. An enclosure with hybrid thermal management for aheat-generating electronic device, said enclosure comprising a passiveheat sink for conducting heat away from said electronic device, a coldskin adapted to slide over the top of said passive heat sink and havinga front wall forming a plurality of air intake ports, and a plurality ofblowers mounted inside said cold skin for drawing air into said coldskin though said air intake ports and then directing said air throughsaid passive heat sink.
 2. The enclosure of claim 1 in which saidpassive heat exchanger includes multiple thermally conductive finsadjacent to said electronic device and extending rearwardly from saidintake ports, said fins being spaced apart from each other forconducting heat away from said electronic device.
 3. The enclosure ofclaim 2 in which said blowers direct air from said intake ports intosaid spaces between said thermally conductive fins.
 4. The enclosure ofclaim 2 in which said thermally conductive fins extend vertically alongsaid air intake ports and above said intake ports, the portions of saidfins above said air intake ports being spaced rearwardly away from saidintake ports to form a space for receiving said blowers in side saidcold skin.
 5. The enclosure of claim 1 which includes air exhaust portsthrough which air can be exhausted from said enclosure.
 6. The enclosureof claim 5 in which said passive heat sink includes a rear wall thatforms said exhaust ports.
 7. The enclosure of claim 2 in which saidpassive heat sink includes side walls forming a space below said finsfor receiving said heat-generating electronic device.
 8. The enclosureof claim 7 in which said passive heat sink includes a front wall closingsaid space below said fins and adapted to transmit signals to saidelectronic device in said space.
 9. The enclosure of claim 8 in whichsaid front wall includes optical ports to transmit optical signals tosaid electronic device.
 10. The enclosure of claim 1 which includes acontroller coupled to said blowers for adjusting the speed of saidblowers based on the temperature in said enclosure.
 11. The enclosure ofclaim 1 in which said electronic device comprises a transceiver.
 12. Theenclosure of claim 11 in which said transceiver is an SFP.